Sculptures or coins which use raised images are known as “cameos”. One of the main gems used to create a cameo is Agate.
Several Agates are naturally discovered where the stone is made up of several distinct coloured layers. To imagine this, think of a white slice of bread sitting on top of a brown slice. The artist carves away at the white piece of bread and leaves a design where the raised image is white on a brown background, thus creating a cameo.
Some of the most impressive examples of cameos date as far back as the 6th century BC, found in amazing sculptures in Greece. Designs are normally portraits of famous people, biblical scenes or religious figures. While Agates are the most common gemstone used to make Cameos, shells and imitation gems are now also frequently used.
Unfortunately today, many cameo’s are created where an object is sometimes carved by laser and then glued or welded onto a background with a contrasting colour. Obviously this is much cheaper than someone spending many hours hand carving the piece out of a single gemstone, where the piece chosen had a natural split of two colours. If you are spending a lot of money on a cameo, make sure that you pay attention with your loupe to where the two layers join.